Asphaltic cement



Reissuecl Nov. 27, 1934 ASPHALTIC CEMENT William C. Ferguson, St. Louis,M0.

N0 Drawing. Original No. 1,878,625, dated September 20, 1932, Serial No.321,771, November 24, 1928. Application for reissue September 19,

1934, Serial No. 744,721

2 Claims.

This invention relates to asphaltic composi tions of the kind generallyreferred to as asphaltic cement.

The asphaltic cements that are now in commercial use may be divided intotwo general classes as follows:

1st. Those that are made of heavy asphalt cut back with naphtha or someother light oil; and

2nd. Those that are made of asphalt combined with water so as to form anemulsion.

Both of the types of asphaltic cement above referred to have oneinherent objectionable characteristic that greatly limits theircommercial use, i. e., they require exposure to the air, in

Accordingly, the asphaltic cements now on the market are not welladapted for use as a filler for large joints, or in work that requiresthe cement to be spread in the form of a relatively thick body on asurface or between two opposed surfaces, due to the fact that too long aperiod is required for the cement to set or harden, for, in the case ofan asphaltic cement of the class first mentioned, it must be exposed tothe air for a considerable time after it has been installed, in orderthat the naphtha used to out back the heavy asphalt may graduallydissipate in the air, and in the case of an asphaltic cement of thesecond class above referred to, the emulsion must be exposed to the airfor a considerable period, in order that the Neither of the classes ofasphaltic cement above mentioned are capable of the being used underwater, due, of course to the fact that they will not harden nor setunless exposed to the air.

One object of my invention is to provide an asphaltic cement which is ofsuch a character or nature that it will dry orset in a reasonable timewhen it is used as a filler for large joints or installed in the form ofa relatively thick mass or body.

Another object is to provide an asphaltic cement that will set or hardenunder Water.

To this end I have devised an asphaltic cement that is composedprincipally of particles of relatively hard and brittle asphalt ingranular form, mixed with a binder which is of such a character ornature that the admixture of same with the granular asphaltic materialwill produce a mass that will remain in a plastic or semi-plasticcondition long enough to enable it to be easily molded, troweled orworked into a joint, but which thereafter will set or harden, even inthe absence of air, or without exposure to the air.

stance or ingredient which will readily penetrate be incorporated in themixture above described, so as to increase its tensile strength bycomingling of the fiber. with the asphalticparticles of the mixture.

The asphaltic material that I prefer to use in producing my improvedasphaltic cement is of the kind that is known commercially as Gilsonite,and which, as is well known, is a relatively hard, brittle asphaltconsisting substantially of pure bitumen and having a melting pointabove 200 F. (ball and ring method). The binder that is mixed with theasphaltic particles contains or comprises a substance or ingredient thatwill readily penetrate into the asphaltic particles, and which, asabsorption by the asphaltic particles takes place, leaves a bondingagent on the asphaltic particles that sets or hardens, even in theabsence of air. One binder that I have found to be well adapted for usein the manufacture of my improved asphaltic cement consists of a rela- 5tively soft petroleum asphalt which has been cut back to a liquid statewith a liquid substance such as naphtha which will be readily absorbedby the hard asphaltic particles, and thus leave on the particles of hardasphalt the relatively soft asphalt that sets or hardens and bonds theasphaltic particles together as the absorption takes place. I wish it tobe understood, however, that other binders may be used, such as containa subinto the asphaltic particles, and thus leave a residue or base thatacts as a bonding agent for the asphaltic particles and which willco-act with same to produce a mass that will set or harden withoutexposure to the air. It is preferable but not absolutely essential thatthe asphaltic material be in the form of relatively coarse particles andrelatively fine particles when said asphaltic material is mixed with thebinder, for when the ingredients are mixed or combined in this manner, Iobtain a mixture or compound that can be easily handled with a trowel orworked into joints, the finer particles of asphaltic material fillingthe voids or spaces between the coarser particles, and thus producing aplastic mass of about the consistency of mortar.

One procedure that I have found to be satisfactory for producing myimproved asphaltic cement is as follows:

Mix together, in any suitable way, approximately 1 lb. of Gilsoniteground relatively coarse, approximately 1 lb. of Gilso-nite ground atrifle finer, approximateb A of a lb. of long asbestos fiber andapproximately of a lb. of

a liquid asphaltic binder of the kind above described.

An asphaltic composition of the kind above described will set or hardenusually in about 48 hours, without exposure to the air and even when itis used under Water, due to the fact that the oil or liquid ingredientof the binder will penetrate readily into the particles of Gilsonite andbe absorbed by same, thus leaving a bonding agent on the particles ofGilsonite that sets or hardens upon the absorption of said oil or liquidingredient by the Gilsonite.

In preparing or producing my improved asphaltic cement it is preferablethat the substance used as the binder be mixed with the granularparticles of asphalt at approximately the time or shortly before thetime the mixture is used, because the hardening, setting orsolidification of the mixture is effected by absorption of the oil orliquid constituent of the binder by the particles of asphalt. Inpreparing my asphaltic cement for the market, the coarse Gilsonite,properly proportioned and mixed with the finer Gilsonite and the fibroussubstance, in case a fibrous substance is used, is shipped in onecontainer, and the substance that is used as the binder is shipped in aseparate container. At or shortly before the time the cement is to beused the binder is mixed in the proper proportion with the coarse andfine asphaltic material and the fibrous substance.

While I have obtained good results with a composition composed ofsubstances of the character mentioned, mixed in approximately the proportions specified, I wish it to be understood that other substances maybe used as the binder and that the percentages or proportions of thevarious ingredients of the mixture may be changed with out departingfrom the spirit of my broad idea, which, briefly stated, consists of anasphaltic cement or asphaltic cement compound composed of twocomplemental parts or portions that are adapted to be mixed together toform a plastic or substantially plastic mass, one of said portionscomprising comminuted hard asphalt having a melting point in excess of200 F., and the other portion consisting of a binding medium composed ofliquid asphalt, i. e., a mixture of an asphaltic material and a diluent,the diluent being of such a nature thatit will rapidly penetrate and beabsorbed by the hard asphalt, even in the absence of air, whereby theasphaltic material of the binding medium Will thicken and harden uponabsorption of the diluent by the hard asphalt, with the result that theentire mixture is converted into a hard mass.

Having thus described my invention, what I claim as new and desire tosecure by Letters Patent is:

1. An asphaltic cement compound or mixture of troweling consistency,composed of two complemental parts which may be mixed with facility, oneof said parts constituting the major portion of the mixture andcomprising comminuted hard asphalt having a melting point in excess of200 F., and the other part composed of an asphaltic substance and adiluent combined in such proportions that the diluent will penetrate andbe absorbed by the hard comminuted asphalt, even in the absence of air,thus causing the mixture to set or harden.

2. An asphaltic cement compound or mixture composed of two complementalparts which may be mixed with facility, one of said parts constitutingthe major portion of the mixture and comprising a comminuted hardasphalt having a melting point in excess of 200 F., and the other partcomposed of an asphaltic substance and a diluent combined in suchproportions that the diluent will penetrate and be absorbed by the hardcomminuted asphalt, even in the absence of air, thus causing the mixtureto set or harden.

WILLIAM C. FERGUSON.

